Such areas with increased thickness in gaskets, especially in cylinder head gaskets usually serve as support. It is for instance known from WO 2004/076893 A1 or EP 1 577 589 A1 to support the beads sealing the combustion openings of the cylinder head gasket by thickened and surface-structured areas which run along the combustion chamber openings, the thickening being achieved through embossing. In addition, the documents mentioned also describe that in areas distant from the combustion chamber openings and closer to the outer edge, the areas also referred to as backland of the gasket, corresponding supporting structures may be present as well. These supporting means consist in undulating or checkerboard like embossments of the gasket layer, in which the depressions and protrusions alternate with each other. The backland support elements do not however serve as so called stoppers, which prevent a complete deformation of the resilient beads, but rather as local height adjustment elements. Preferably, these height adjustment elements extend along the outer edge of the gasket, preferably at the shorter edge. The height adjustment elements mainly aim at preventing shape distortions on the areas to be sealed, especially of the cylinder head. The simultaneous presence of supporting elements and height adjustment elements both along the combustion chamber openings and the backland of the gasket constitutes a considerable improvement compared to such gaskets in which the resilient combustion-chamber beads are accompanied by supporting elements on the side of the combustion chamber only. Nevertheless, even with both supporting elements and height adjustment elements, shape distortions can not always completely and reliably be prevented.
It is therefore the object of the invention to provide a metallic flat gasket which reliably prevents shape distortions of the areas between which the gasket is installed. The gasket shall be easily and inexpensively produceable and adaptable for various kinds of surfaces to be sealed.
The solution of this object is achieved by a metallic flat gasket according to claim 1. Preferred embodiments are described in the subordinate claims.